Waste impoundments, landfills, ash impoundments and the like face a complex web of regulations that present significant compliance risks to manage. Mitigating the environmental risks that such waste containment facilities pose and meeting compliance requirements are significant challenges.
Many waste impoundments are of similar construction, including for example large scale basins, surrounded by soil berms or dikes to create storage for waste, and often times constructed without a liner. Consequently, common concerns and technical challenges include waste located below the water table that can serve as a continual source for leaching of waste contaminants to groundwater; placement of saturated waste within the impoundment can lead to an increase in hydraulic head above the naturally occurring groundwater table exacerbating contaminant leaching; historic infrastructure near and within waste impoundments can serve as potential migration pathways for leaching from the impoundment to surface water and groundwater and also contribute to geotechnical instability; and saturated and differential hydraulic conditions can potentially compromise impoundment geotechnical stability along surface water bodies.
To fully resolve these technical challenges and considerations, the waste must be hydraulically isolated from the groundwater and the geotechnical strength characteristics maintained or enhanced to decrease the potential for instability. Such a need has not previously been met, particularly for existing waste containment facilities, such as waste impoundments, landfills, ash impoundments and the like, where waste is already in place within the waste containment facility. These concerns are applicable and persist at numerous types of waste facilities, including, but not limited to, waste impoundments for coal combustion residuals (ash), mine tailings, drill cuttings and fluids, confined disposal facilities for dredged sediments, acid tar lagoons, and abandoned municipal landfills.
Thus, there is an established need for methods, systems and devices which can provide a technically sound and low cost closure/remediation approach for waste impoundments to comply with regulatory requirements and mitigate existing environmental concerns.